function startmenu()
{
	document.getElementById('tumb').style.display = "none";
}

function menufunc(menuId)
{
	if(document.getElementById(menuId).style.display == "none")
	{
		startmenu();
		document.getElementById(menuId).style.display = "block";
	}
	else
	{
		startmenu();
	}
}

function changeImage(filename)
{
   document.getElementById('mainimage').src = filename;
}

function showHide(eltID)
{
    var elt=document.getElementById(eltID);
    
    if(elt.style.display=='block')
    {
        elt.style.display='none';
    }
    else
    {
        elt.style.display='block';
    }    
}